Public officials play the blame game over MH17 crisis

Barack Obama has been cautious to avoid playing the blame game over Malaysia Airlines flight MH17, but US vice president Joe Biden and US senator John McCain have squarely laid the blame on Russia, while other officials say the fault is Ukraine's.

The news of the crash and its possible cause came at a tense time, the day after the United States announced new sanctions against Russian banks over Moscow's role in the Ukrainian conflict.

In a remarkable coincidence, Mr Obama found out about the disaster while on the phone to Russia's president Vladimir Putin. It was a call that had been arranged earlier at the Kremlin's request to talk about the sanctions.

Mr Obama issued a cautious public response that avoided blaming anyone for the incident.

"It looks like it may be a terrible tragedy," he said. "Right now we're working to determine whether there were American citizens on board. That is our first priority, and I've directed my national security team to stay in close contact with the Ukrainian government," he said.

"A Malaysian aircraft ... has been shot down, not an accident. Blown out of the sky."

US vice president Joe Biden

"The United States will offer any assistance we can to help determine what happened and why."

However, vice president Joe Biden was not so temperate in his language.

"A Malaysian aircraft ... apparently, and I say apparently because we don't have all the details ... has been shot down. Shot down, not an accident. Blown out of the sky."

"Vladimir Putin's continued to try to foment discontent. This is a result of it and there'll be hell to pay."

John McCain

"This is truly a grave situation. Nearly 300 souls have been lost. The families have our consolation and our prayers."

US senator John McCain did not hold back in his public statements, directly laying the blame on the Russian president.

"Vladimir Putin's continued to try to foment discontent. This is a result of it and there'll be hell to pay."

Ukraine puts blame squarely on Russia

Ukrainian president Petro Poroshenko has blamed Russia for shooting down the jet as well as a transport plane.

"I would like to bring your attention to the fact that we are not calling it an accident or a disaster but an act of terrorism," said Mr Poroshenko.

"I just finished a conversation with the prime minister of the Netherlands. I offered our condolences on behalf of the Ukrainian people and invited Dutch experts to open an investigation of this act of terrorism."

The pro-Russia rebels have denied they had anything to do with the loss of MH17 and have been quick to issue a counter-accusation.

The prime minister of the self-proclaimed People's Republic of Donetsk, Aleksander Borodai, said the passenger plane has been shot down by Ukrainian air forces.

Mr Bordai said the crash was a purposeful attack from the Ukrainian government. "To tell the truth this is a provocation on purpose."

It is thought only a long-range surface-to-air missile, possibly guided by radar, would be capable of bringing down the Malaysian plane at its reported height of 10,000 metres.

It is not clear whether pro-Russian separatists had such capabilities. The former UK ambassador to Russia, Sir Tony Brenton, is another public official to weigh in on the crisis.

"The secessionists have used tanks and they don't find those lying on the street," Sir Tony said.

"They have supplies of relatively sophisticated weapons and it would be very damaging for them and for the whole Russian case if they now have the sort of weapons which shoot down civilian aircraft but of course even more damaging, if it turns out that the missile, came from the Russian side of the border."

There is no confirmation that MH17 was shot down but the aircraft was reportedly not in any difficulties before contact was abruptly lost.

An arrivals information page for Kuala Lumpur airport lists the status of the flight as unknown.

Finding out the truth about who is responsible won't be simple, already Ukrainian investigators say they are being prevented from getting to the site of the crash by pro-Russian separatists.

Questions are being raised over Ukraine's right of authority to conduct this investigation, given its part in the conflict.

There should be plenty of evidence available and not just on the ground, far more than there was for Malaysia Airlines flight 370, which went missing over the Indian Ocean in March.

This tragedy took place over one of the most closely watched regions in the world, where NATO and the US have been monitoring the movements of Russian troops on the Ukrainian border from the sky.

Passenger planes being shot down is a rare occurrence but it's not unknown.

The US Navy in fact shot down an Iranian passenger jet in the Persian Gulf by mistake in 1988, the accident happened in Iranian airspace, killing the 290 on board.

The Ukrainian air force shot down a Russian plane in 2001 during a military training exercise, when a missile missed its target, and hit the passenger jet.

Aviation expert Andrew Charlton says while a passenger plane clearly looks different from a military aircraft, mistakes can happen.

"It is quite difficult to make the distinction. Aircraft are moving very fast; they're very, very high. At this point it was at 10,000 metres, 33,000 feet. That's a long way up. It's very hard to tell them apart," said Mr Charlton.

International airlines who were still routing their planes over the region, immediately announced they would change their flight paths.